No, this is not possible. You need to initiate the review again. This is because the review server information is embedded inside the PDF and when you change the review server, the JavaScript embedded in PDF still refers to the old server. So Tracker is unable to locate the review PDF.

If the old review has comments by other reviewers, you can save it as an archive and initiate review on new server on this new PDF. This way all the review comments can be retained in the PDF but they will be published "on behalf of" the initiator now.

You can very much edit the DB in all the releases. Tracker keeps track of its reviews' list via the DB. But here the javascript is embedded inside the PDF (this is embedded when you initiate a review) and that is not getting changed when you change the review server. Tracker has no role to play here. Hope this helps.